1 //===- CallDescription.h - function/method call matching --*- C++ -*-===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 /// \file This file defines a generic mechanism for matching for function and 10 /// method calls of C, C++, and Objective-C languages. Instances of these 11 /// classes are frequently used together with the CallEvent classes. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #ifndef LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_CALLDESCRIPTION_H 16 #define LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_CALLDESCRIPTION_H 17 18 #include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h" 19 #include "llvm/ADT/ArrayRef.h" 20 #include "llvm/ADT/Optional.h" 21 #include "llvm/Support/Compiler.h" 22 #include <vector> 23 24 namespace clang { 25 class IdentifierInfo; 26 } // namespace clang 27 28 namespace clang { 29 namespace ento { 30 31 enum CallDescriptionFlags : unsigned { 32 CDF_None = 0, 33 34 /// Describes a C standard function that is sometimes implemented as a macro 35 /// that expands to a compiler builtin with some __builtin prefix. 36 /// The builtin may as well have a few extra arguments on top of the requested 37 /// number of arguments. 38 CDF_MaybeBuiltin = 1 << 0, 39 }; 40 41 /// This class represents a description of a function call using the number of 42 /// arguments and the name of the function. 43 class CallDescription { 44 friend class CallEvent; 45 using MaybeCount = Optional<unsigned>; 46 47 mutable Optional<const IdentifierInfo *> II; 48 // The list of the qualified names used to identify the specified CallEvent, 49 // e.g. "{a, b}" represent the qualified names, like "a::b". 50 std::vector<std::string> QualifiedName; 51 MaybeCount RequiredArgs; 52 MaybeCount RequiredParams; 53 int Flags; 54 55 public: 56 /// Constructs a CallDescription object. 57 /// 58 /// @param QualifiedName The list of the name qualifiers of the function that 59 /// will be matched. The user is allowed to skip any of the qualifiers. 60 /// For example, {"std", "basic_string", "c_str"} would match both 61 /// std::basic_string<...>::c_str() and std::__1::basic_string<...>::c_str(). 62 /// 63 /// @param RequiredArgs The number of arguments that is expected to match a 64 /// call. Omit this parameter to match every occurrence of call with a given 65 /// name regardless the number of arguments. 66 CallDescription(CallDescriptionFlags Flags, 67 ArrayRef<const char *> QualifiedName, 68 MaybeCount RequiredArgs = None, 69 MaybeCount RequiredParams = None); 70 71 /// Construct a CallDescription with default flags. 72 CallDescription(ArrayRef<const char *> QualifiedName, 73 MaybeCount RequiredArgs = None, 74 MaybeCount RequiredParams = None); 75 76 CallDescription(std::nullptr_t) = delete; 77 78 /// Get the name of the function that this object matches. 79 StringRef getFunctionName() const { return QualifiedName.back(); } 80 81 /// Get the qualified name parts in reversed order. 82 /// E.g. { "std", "vector", "data" } -> "vector", "std" 83 auto begin_qualified_name_parts() const { 84 return std::next(QualifiedName.rbegin()); 85 } 86 auto end_qualified_name_parts() const { return QualifiedName.rend(); } 87 88 /// It's false, if and only if we expect a single identifier, such as 89 /// `getenv`. It's true for `std::swap`, or `my::detail::container::data`. 90 bool hasQualifiedNameParts() const { return QualifiedName.size() > 1; } 91 92 /// @name Matching CallDescriptions against a CallEvent 93 /// @{ 94 95 /// Returns true if the CallEvent is a call to a function that matches 96 /// the CallDescription. 97 /// 98 /// \note This function is not intended to be used to match Obj-C method 99 /// calls. 100 bool matches(const CallEvent &Call) const; 101 102 /// Returns true whether the CallEvent matches on any of the CallDescriptions 103 /// supplied. 104 /// 105 /// \note This function is not intended to be used to match Obj-C method 106 /// calls. 107 friend bool matchesAny(const CallEvent &Call, const CallDescription &CD1) { 108 return CD1.matches(Call); 109 } 110 111 /// \copydoc clang::ento::matchesAny(const CallEvent &, const CallDescription &) 112 template <typename... Ts> 113 friend bool matchesAny(const CallEvent &Call, const CallDescription &CD1, 114 const Ts &...CDs) { 115 return CD1.matches(Call) || matchesAny(Call, CDs...); 116 } 117 /// @} 118 }; 119 120 /// An immutable map from CallDescriptions to arbitrary data. Provides a unified 121 /// way for checkers to react on function calls. 122 template <typename T> class CallDescriptionMap { 123 friend class CallDescriptionSet; 124 125 // Some call descriptions aren't easily hashable (eg., the ones with qualified 126 // names in which some sections are omitted), so let's put them 127 // in a simple vector and use linear lookup. 128 // TODO: Implement an actual map for fast lookup for "hashable" call 129 // descriptions (eg., the ones for C functions that just match the name). 130 std::vector<std::pair<CallDescription, T>> LinearMap; 131 132 public: 133 CallDescriptionMap( 134 std::initializer_list<std::pair<CallDescription, T>> &&List) 135 : LinearMap(List) {} 136 137 template <typename InputIt> 138 CallDescriptionMap(InputIt First, InputIt Last) : LinearMap(First, Last) {} 139 140 ~CallDescriptionMap() = default; 141 142 // These maps are usually stored once per checker, so let's make sure 143 // we don't do redundant copies. 144 CallDescriptionMap(const CallDescriptionMap &) = delete; 145 CallDescriptionMap &operator=(const CallDescription &) = delete; 146 147 CallDescriptionMap(CallDescriptionMap &&) = default; 148 CallDescriptionMap &operator=(CallDescriptionMap &&) = default; 149 150 LLVM_NODISCARD const T *lookup(const CallEvent &Call) const { 151 // Slow path: linear lookup. 152 // TODO: Implement some sort of fast path. 153 for (const std::pair<CallDescription, T> &I : LinearMap) 154 if (I.first.matches(Call)) 155 return &I.second; 156 157 return nullptr; 158 } 159 }; 160 161 /// An immutable set of CallDescriptions. 162 /// Checkers can efficiently decide if a given CallEvent matches any 163 /// CallDescription in the set. 164 class CallDescriptionSet { 165 CallDescriptionMap<bool /*unused*/> Impl = {}; 166 167 public: 168 CallDescriptionSet(std::initializer_list<CallDescription> &&List); 169 170 CallDescriptionSet(const CallDescriptionSet &) = delete; 171 CallDescriptionSet &operator=(const CallDescription &) = delete; 172 173 LLVM_NODISCARD bool contains(const CallEvent &Call) const; 174 }; 175 176 } // namespace ento 177 } // namespace clang 178 179 #endif // LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_CALLDESCRIPTION_H 180